Base and contact for electrical devices



Nov. 23, 1948.

w. MAKENNY BASE AND CONTACT FOR ELECTRICAL DEVICES 2 Shuts-Shoot 1 FiledDec. 29, 1943 INVENTOR I, If) A's/10y BY m ATTORNEY Nov 23, 1948:

BASE AND CONTACT FOR BLBTRICAL DEVICES Filed Dec. 29 1943 2 Sheets-Shoot2 "Wmm ATTORNEY w. IMAKENNY 2,454,326 I Patented Nov. 23, 1948 BASE ANDCONTACT FOR ELECTRICAL DEVICES William Makenny,

Mountainview, N. 1., we to Westinghouse Electric Corporation, Eastllttshurgh, 2a., a corporation of Pennsylvania Application Deumber 29,1943, 861181 No. 510,014

comma (c1. ll3- 361) This invention relates to bases for electricaldevices, and more particularly to such adapted for fluorescent lamps.

The principal object of myinvention, gener ally considered, is toprovide a pin for a pressed base and of such a formation, as comparedwith that of the base, that it holds tightly in place.

Another object of my invention is to provide a pin, preferably'i'ormedof. brass, with a, hollow collar relatively long axially and disposedintermediate its ends, that portion of 'said pin on one side of saidcollar preferably being relatively long and generally cylindrical toform'the outer contact element, and that on the-other side being shorterand'tapered for part or its length from a diameter larger than that ofsaid cylindrical portion to one corresponding therewith, and thencontinuing generally cylindrical to near the end, whereby itmay bestaked in a base of phenolformaldehyde or thermosetting resin or otherbase material and provide a secure and lasting connection therewith.

A further object of my invention is to provide a base of Bakelite, glassor other suitable material formed with contact pins as above describedheld tightly in place by radial as well as axial stress.

A still further object of my invention is the provision of a method ofstaking or connecting contact pins as above described to bases.comprising inserting such pins in a lower die, fitting a base thereover,forcing tions of said pins by means of a spring plunger, prestaking thepins with apyramidal tool to cut and expand their upper ends, partiallycollapsing the hollow collar thereof, and finally staking the pins witha cylindrical tool to crimp the expanded end portions of the pins overthe base bottom wall and further collapse the collar, resulting in atight fit therebetween due to radial stress of the tapered orfrusto-conical portion of the pin in the base aperture, in addition tothe axial stress caused by the staking tool.

the base over the tapered por- Other objects and advantages of theinvention,

relating to the particular arrangement and construction of the variousparts, will become apparent as the description proceeds.

Referring to the drawings which show to scale only one embodiment of myinvention:

' Figure l is a fragmentary side elevational view, full size in theoriginal drawing, of a discharge device embodying my invention.

Figure 2 is a fragmentary elevational view, full. size in the originaldrawing, with parts in vertical section, of astaking machine embodyingmy invention.

- after a. plunger has Figure 3 is a diagrammatic plan view or a staking machine shown in Fig. 2, reduced in scale.

Figure 4 is an axial sectional view, full size in the original drawing,with the base pins in elevation, of a base after such pins have beencompletely staked in place.

Figure 5 is an enlargedaxial sectional view of a pin embodying myinvention,and in position for connection with a base.

Figure 6 is a view corresponding to Fig. 5, but showing the position ofthe parts when the base has first been fltted over said pin.

Figure '1 is a view corresponding to Fig. 6 but showing the next;position of the parts, that is, forced the base down over the topportion 0! the pin so that it tightly grips the tapered orfrusto-conical portion thereof.

Figure 8 is a view corresponding to Fig. 7, but showing the nextposition where the pre-staking pyramidal tool has engaged the upperportion of the pin and cut and expanded the same.

Figure 9 is a view corresponding to Fig. 8, but showing the nextposition where the final staking tool has crimped the spread portions ofthe pin over the bottom wall of the base. I

Figure 10 is a plan view after completion of the staking in accordanceupper portion of the pin after the completion of the staking operation.

Referring to the drawings in detail, like parts being designated by likereference characters, there is shown in Fig. l a discharge device iiwhich may be a fluorescent lamp andconsist of an enclosing preferablytubular envelope l2, and filamentary electrodes l3 and il at oppositeends held by flare devices l5 and i6, which are respectively sealed toand close opposite ends of said envelope. To each end of the envelope isapplied a base I! which, in the present embodiment, comprises a cupmember 18 of an insulating thermosetting resin of the condensing typ towhich are staked-a pair of contact pins l9 and ii. Such are desirably ofthe type known as head cha pins, as manufactured by the Bead ChainCompany, Bridgeport, .Connlecticut. They are made from strip metal suchas l bras-s, gilding metal, steel, or the like, formed by dies on aswaging machine. They may vary dimensionally in accordance with the sizeof the device with which used, but all are desirably bulged or beaded toprovide a collar 22 between the ends, with shanks extending above andbelow said collar.

In the staking operation, the shorter, isinserted in a hole in the baseand fastened or anchored by turning over the end with Fig. 9, showingthe Y one end, preferably 44, resulting of the pin inside of the moldedshell by the stak- I ing tool. in the past, the part of each pinreceived in the hole in the base has been cylindrical, with the resultthat in staking the only stress available for holding the pins in place,after final assembly, was that due to the crimping of the upper endportion, causing axial contraction, as the pins were initially made soas to fit the holes in the base to which connected without being forcedin place, and during the staking operation the slight axial compressionof the bead or collar 22 drew the metal of the cylindrical portion inthe base hole radially inward, thereby further increasing the loosenessof the fit.

It is necessary that there be a slight clearance between the shank ofthe pin received in the base and the hole in which it is received. Inaccordance with my invention I leave this same clearance, which isdesirably about .002", but form a portion of said shank frusto-conical,or increasing from said cylindrical portion toward the collar 22 to adiameter slightly larger than'the receiving aperture in the cup memberl6, so that there may be a forced fit between the cup member and pinwhen'the former is forced into engagement with the collar, whereby eventhough the collar is constricted axially during the staking operation,thereby pulling in on the shank to slightly decrease its diameter, suchoperation will not be great enough to destroy the tightness of the litbetween said pin and cup member.

One embodiment of my preferred form of pin is shown enlarged in Figs. to10, inclusive, as compared with the full size views of Figs. 2 and 4,and the reduced diagrammatic view of Fig. 3. Referring first to Fig. 5,it will be seen that one preferred embodiment of my pin involves anoverall length of about .855" and a normal diameter of ,4,", a toleranceof .002" being allowed. The thickness of the metal forming the hollowpin I9 illustrated is desirably about or .015". The lower or longerportion 23 of the pin is desirably .59" from the hollow collar 22, whichis desirably .07" long or axialy. The portion 23 is desirablycylindrical and .125" in diameter to near its free or lower end 25,where the metal is bent inward or contracted to leave an aperture 26,reduced in diameter as compared with the interior of the pin.

The upper or shorter section 21 of the pin beyond the collar 22 isdesirably .005" larger in diameter than that of the cylindrical portion23, say .130" near the collar, tapering for about half the distance toits upper end, or to the point 28. where it becomes the same size asthat of the part 23. that is, .125" in diameter, and from there itremains cylindrical to near its upper or free end. where the metal isturned in to leave an aperture 29, of reduced diameter as compared withthe interior.

The cup or shell l3 of the base I! has pinreceiving apertures 3| and 32which are desirably truly cylindrical and of a, diameter allowing justthe right clearace. For a pin of the size described, the diameter shouldbe .128" or between .127" and .129". This I3 is fitted over the the pin,reaching loose fit semi-tapered end 2'! of as shown in Fig. 6, it bindsbefore the collar 22 while making a slightlywith regard to thecylindrical portion.

means that when the cup In Fig. '7 is shown the cup l8 after having beenforced down over the pin by the spring plunger in compression of thematerial of the cup at the point 33 and a movement thereof sure asheretofore. and

along the frusto-conical portion 21 to almost engage the collar 22.

As shown in Fig. 8, the prestaking operation of the pin in the bottomwall of the base involves the forcing of a tool 34 into the reducedaperture 29 of the pin, cutting the metal apart and spreading it,preferably as four sections 35, 36, 31, and 40, at the same time causinga slight axial compression of the collar 22, which allows the cup l8 tofurther approach it. This action also causes a corresponding slightradial contraction of the frusto-conical portion 21 near the said c01-lar, but one not enough to destroy this tight fit of the cup withrespect thereto, at the same time slightly expanding the upper end ofthe pin so that the fit is tight along substantially the full length ofthe engagement between the portion 21 of the pin and bottom wall of thebase cup l8.

In Fig. 9 the final staking operation is illustrated in which thesections 35, 36, 31 and 40, into which the upper portion of the pin hasbeen cut and separated, are flattened by the tool 45 approximately tothe inner surface of the lower wall of the cup l8, while at the sametime said lower wall is forced into engagement with the collar 22, thelatter being simultaneously further flattened or decreased in axialdimension as illustrated.

Considering the foregoing operations in connection with a practicaldevice for performing them, as illustrated in Figs. 2 and 3, there isshown a machine 38 comprising a rotatable base member 39 holding aplurality of dies 4|, in this instance eight, said dies each having apair of apertures 42 and" 43for receiving a corresponding number ofpins, which are fed thereto at the position designated automatic pinfeed in Fig. 3. Ejecting plungers 24 in the member 39, allned with theapertures" and 43, may be provided for automatically discharging thebases after completion.

The next position, designated base feed, is where a base is fitted overa pair of pins or a die after the base member 39 has moved through 45 orto of a revolution. After moving a quarter of a revolution further, thebase is engaged by a spring plunger" 44 and resiliently pressed over thepins, as viewed in Fig. 2.

Upon moving 45' more the pins are encountered by a pre-staking tool 34and cut or slit longitudinally and spread, as viewed in Fig. 2

and discussed in connection with Fig. 8. As a "final staking operation,the base, after advancing another 45 further, is encountered by. thefinal staking tool 45 which flattens the spread portions 35, 36, 3'! and40', over the bottom portion of the base, as viewed in Fig. 2 and aspreviously described in connection with Fig. 9.

From the foregoing, it will be seen that I have devised a, novel form ofcontact pin particularly adapted for fluorescent lamp bases, and sodesigned with respect to its base cup that it may be staked tighter in abase without as much pres after staking therein it is secure and tight,not only axially but also radially, that is, not depending solely on thepressure between the bead or collar and the turnedover part on theinside of the base, thereby avoiding previous trouble encountered inconnection wiht: such devices due to looseness of the contact p Althougha preferred embodiment of my invention has been disclosed, it will beunderstood that modifications may be made within the scope and spirit ofthe appended claims.

ma ses 1 5 I claim: Y 1. A hollow metal pin the outer surface of whichis divided by a hollow peripheral collar, that portion of said pin onone side of said collar being relatively long and generally cylindrical,

and that portion of said pin on the other side of said collar beingpreformed to taper therefrom slightly for about half the distance to theend of the pin to a smaller diameter and then continue generallycylindrical in order to provide a tight radial fit when inserted in acylindrical aperture, of diameter slightly smaller than the maximumdiameter of said tapering portion, but

slightly larger than said cylindrical portion, in a base for anelectrical device to form a contact therefor.

2. A hollow metal pin to function as a contact for an electrical deviceand formed with a hollow aperture, and that part of said pin on theother side of said collar being about .195" long, and preformed, forforce fit in a cylindrical aperture in said base about .128" indiameter, to start out about .005 larger in diameter than the longercylindrical portion, taper for about half the distance toward the otherend, to a diameterequal to that of said cylindical portion, and thencontinue to near said end as cylindrical, with the metal at the extremeend portion turned in to reduce the size of the aperture, in order toprovide for a tight radial fit in said aperture.

5. A hollow metal pin to function as a contact for an electrical deviceand formed with a hollow peripheral collar dividing it unequally intotwo parts, the. larger part of its length being generally cylindricalfrom near one end to said collar and the part of said pin on the otherside peripheral collar dividing it unequally into two parts, the largerpart of its length being generally cylindrical from near one end to saidcollar and the part of said pin on the other side of said collar beingpreformed to be frusto-conical for about half the distance from thecollar to the end to a slightly reduced diameter and generallycylindrical therefromto adjacent its end in order to provide a tightradial fit when inserted in a cylindrical aperture, of diameter slightlysmaller than the maximum diameter of said tapering portion, but slightlylarger than said cylindrical portion, in a base for an electrical deviceto form a contact therefor, both ends of said pin being rounded to formopenings of diameters smaller than that of the pin interior.

3. A hollow metal pinto function as a contact for an electrical deviceand formed with an intertion and then continue to near the end as crimedrical. with the metal of the extreme end portion turned in to reducethe size of the aperture, in order to provide a tight radial "fit wheninserted in a cylindrical apertureabout .128" in diameter.

4. A hollow pin to function as a contact for.

a base of thermoaetting resin of the condensing type for an electricaldevice and formed of metal about .015" thick, with an intermediateportion bulged outwardly to provide a hollow collar dividing itunequally into two parts,- said pin having an over-all length of about.855", the collar having an axial length of about .07", the longer pinpart to. one side of said collar being generally cylindrical, about .59"long and about in outside diameter, except at its free end wherethemetalisturnedintoreducethesileofthe 274,874

of said collar being preformed to be frustoconical for about half thedistance from the collar to the end to a slightly reduced diameter andgenerally cylindrical therefrom to adjacent its end in order to providea tight radial fit when inserted in a cylindrical aperture, of diameterslightly smaller than the maximum diameter of said tapering portion, butslightly larger than said cylindrical portion, in a base for anelectrical device to form a contact therefor.

6. A hollow metal pin to functionas a contact for an electrical deviceand formed with an intermediate portion bulgedoutwardly to provide ahollow collar dividing it unequally into two the largerpart beinggenerally cylindrical from near one end to said collar and about 3/ inoutside diameter, and that part of said pin on the other side ofsaidcollar being preformed to start out about five thousandths of aninch larger in diameter than the cylindrical portion and taper, fornearly half the distance to the other end, to the same diameter as thatof said cylindrical portion and then continue to near the end ascylindrical, in order to provide a tight radial ht when inserted in acylindrical aperture about .128 in diameter.

. WILLIAM MAKENNY.

sameness cm The following references are of record in the file of thispatent:

UNITED m mm'rs matron Pam-rs 1 ountry 1 nm em Britain m Number Number

